Commit 45152dc removed clearing of L2CACHE flag in arc_read_done() and
moved related code in l2arc_write_eligible(). After careful code
inspection arc_read_done() is not bypassed in the case of prefetches.
Thus restore the old behavior.
Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: adam moss <c@yotes.com>
Signed-off-by: George Amanakis <gamanakis@gmail.com>
Closes#10951